h a l f b a k e r yLeft for Bread
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As my esteemed colleague [MaxwellBuchanan] pointed out
otherwhere on this site, a system was devised in the 1920s
for lowering a person or object from an aeroplane by
means of a rope. It involved the plane flying in circles
while the lowered person remained relatively still at the
centre.
Howevertheless,
this is relatively little fun, and involves
only one aeroplane which has to fly in circles.
So.
Instead, we have two aircraft, flying one behind the other
and, say, 1000ft apart at an altitude of 1000ft.
The person to be lowered (and I would like to volunteer,
personally, that [8th] be that person in the first instance)
sits in the back of the front 'plane, which (and this is
important) has a tailgate opening.
A non-stretchy rope is attached to this person's harness,
and runs from there to a second attachment point on the
rearmost aeroplane.
At an appropriate moment, said person steps off the tail
ramp of the frontmost aeroplane.
Viewed from the perspective of the second aeroplane, the
person will swing, pendulum-like, underneath the
aeroplane.
With some careful control of flying speed, the person will
reach the bottom of the arc and be:
(a) At exactly zero feet above the ground
(b) Travelling backwards, with respect to the second
aeroplane, at a certain speed V which will
(c) exactly match the groundspeed of the aeroplane.
Assuming that all of these criteria have been met, the
person has merely to press the quick-release button on the
rope, to be left standing calmly after the experience of a
lifetime (potentially).
Skyhook
https://www.youtube...watch?v=u4xlYpKrCnU
hard to believe but totally true [xenzag, Jul 07 2014]
[link]
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You really need to see someone about this split personality problem your experiencing [Max]. |
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//I would like to volunteer, personally, that [8th] be that person// |
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Makes sense, as a borg collective he's got plenty of spare bodies after all. |
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//the person has merely to press the quick-release button on the rope, to be left standing calmly after the experience of a lifetime (potentially)// |
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Or if it all goes horribly wrong ends up as rather a lot of geography, as a consolation prize he (or she) gets a touching eulogy from their nearest & dearest, I find it slightly disturbing that I'd actually like to try this (after 8th). |
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Well, I'm afraid that I'm going to agree and disagree. |
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First, I agree about the test pilot part. |
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Second, the rope is going to immediately go slack as
the downward acceleration will pale into
insignificance compared to the deceleration caused
by the wind. |
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And don't think you can go changing the rope to a
pole, either. How you gonna get a 1000ft pole as carry
on? |
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[Ling] the behindermost aeroplane should be at a somewhat higher altitude so the initial drop angle is not vertical. |
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This is clever, and has a certain surface patina of logic to it. However, like [Ling], I worry that air resistance will cock the whole thing up and lead to the deaths of legions of your test subjects. |
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//the rope is going to immediately go slack// |
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I rather thought there'd be something like an extendible dog leash mechanism to prevent slack as the rope pays out, was sure I'd seen such in use as an alternative to landing or a parachute for fast yet controlled drops from helicopters & the like. |
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The friction / grip applied by these as it pays out also keeps the speed of decent to non-terminal velocities. |
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Or have I misunderstood your concern [Ling]? |
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[Skewed] "friction / grip" -> "gription" (q.v) |
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Well, at a pinch we could always have the rearmost
aeroplane in front, and the foremost one behind. |
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Well, that does make a lot more sense. |
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// careful control of flying speed // |
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We wish to point out that for fixed-wing aircraft, there is a well-
defined range of velocity within which flying is possible. |
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Actually, there may be a way to test this without
terminal deceleration (isn't suddenly stopping from
more than 20mph, terminal?). |
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If you hung from a plane, and then powered forwards
in ever more increasing arcs*, just like a swing but
from the moving plane, there may be an optimum
point where air resistance and the swing downwards
combine to cancel out the planes velocity. If the rope
starts to get slack during the increasing arc phase of
the experiment, then stop and find someone else to
carry on the experinent. |
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*The plane could accelerate/decelerate |
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Do you actually need a second plane? I think you could have one big plane which could pay out a sort of gliding drogue. You'd need 2 pieces of rope - one to pull the drogue and one to dangle the minion.
Then when you've deployed your volunteer you can winch it back in and attach another. |
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//for fixed-wing aircraft, there is a well- defined
range of velocity within which flying is possible.// |
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Quite so. This might work best from a pair of
biplanes, many of which have stall speeds in the
few-tens of mph. It might also require the droppee
to be very dense. [8th]? |
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<Shuffles behind [Skewed], points meaningfully> |
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// "I find it slightly disturbing that I'd actually like to try this " // |
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Hey, we're not going to stand in your way ! |
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Ohh, look ! There, on the ground ! Money ! |
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<Tries to surreptitiously attach large carabiner on a long rope to the back of [Skewed]'s belt> |
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[8th] I'll buy you a ticket to the National Railway
Museum if you go guinea-pig on this one. |
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[Skewed], if it ends badly the ticket's yours. |
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Check out the link. Skyhook rescue system. |
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The link is cool (though not as cool, clearly, as the
present invention). |
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However, I'm unhappy about the way they tested it
on a sheep first. Sheep are expensive, sentient
beings. |
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[8th] have you got that harness on yet? |
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I remember reading about a helicopter based people deployment system that's similar to this. The people hang from the heli at the end of long ropes, and the chopper does a brief flaring maneuver, timed so the people swing forward, come to a complete stop exactly where they want to get off (whereupon they unclip), by which time the chopper is moving off at a smart pace. The idea being, say, to drop people off onto a rooftop without people in the building knowing it was being done. The heli pauses so briefly in the maneuver that there's a good chance no one realises what's been done. anyhow, it's similar in that it uses pendular motion. |
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// National Railway Museum // |
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<picks up parachute harness> |
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+1: The sound of the sheep in the skyhook video |
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//<picks up parachute harness>// |
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Ah - we thought a full parachute harness would be a
bit over the top for the first tests. If you just slip
your arms into the two loops in the string, and hold
very tightly, it'll probably be alright. |
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OK, done that. So what happens noTWOINGGGGGGG
EEEeeeeeeeaaaaaahhhhhh .....
.
.
.
.
<distant thud> |
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No sheep baaaaaaaaaaaa sound? |
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<faint groans and whimpering> |
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[hippo], it only just occurred to me to Google gription, I didn't know it was a real word, thanks. |
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Where's [8th] gone I thought I heard him here a minute ago?... is that his National Railway Museum ticket on the floor there?, oh well, if he doesn't want it. |
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Well, the dummy run with [8th] went about as
well as expected. It's been very useful to be able
to find the weak points in the arrangement. |
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Admittedly, trying to drop [8th] directly into the
National Railway Museum was a bit overambitious.
Who knew they'd built that new shed? Still, [8th]
seemed to enjoy it. At least, when I said "Did you
enjoy it?", his left eye blinked once. Unless it
was a twitch. It was hard to tell while he was
wearing all that corrugated iron. |
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With respect to the rear plane, this person would be travelling at a maximum of terminal velocity for a falling person I think, presuming they conserved their speed. That's about 200 km/hr, seemingly feasible for a near-zero groundspeed. |
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I'll be sure and look for it in the next Bond film. |
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Presumably this could also operate in reverse for picking up a person from the ground. |
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Hey! Did you see that?! [8th] twitched! I told you
he'd be fine. |
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Well duh!, he's got nanites, could take them a while to repair all that damage though, not sure how good they are at repairing brain damage, do you think he hit his head? |
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I'm not sure. I thought I saw a lot of bruising and
puffiness around the face and nose, until I realized I
was looking at the wrong end. |
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<bzzt> .... <fsssszt> .... |
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Maybe I'm missing something but it seems to me like although that person may have been stationary in relation to the second aircraft, it would be pretty much not in relation to the ground. When I say ground, I say air. So if the person unclipped while on top of the second aircraft it would be a pretty short stay. The person would be projected backwards, possibly embedding herself into the plane's tail. |
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